Various techniques for displaying images exist. A typical digital projector has the following parts in order: Illumination system, optical modulator assembly and a projection lens system. A light source assembly is used by the illumination system to illuminate the optical modulator assembly and the projection lens system images the effective optical modulator surface on a screen.
The illumination system typically consists of a light source assembly, color wheel, IR/UV filters, light source homogenizer, and an illumination relay made up of lenses/mirrors. An optical modulator assembly can consist of one or more optical modulators such as (DMD, LCos, LCD etc.). When certain optical modulator assemblies and the light source assemblies are used, a color wheel and IR/UV filters can be omitted depending upon the design architecture. A projection lens system typically consists of lenses and mirrors.
A light source assembly typically consists of one or more light sources, such as LEDs, lasers, incandescent arc lamps, such as Hg, Xe or metal halide.
In a typical system, significant light is lost in the coupling within the illumination system with regard to the light source assembly. One of the reasons for this loss is geometric shape mismatch between the spatial distribution pattern of the light source and the collection of light by the illumination relay. Hence, system efficiency is significantly reduced.